This study is designed to detect and characterize effects of selected anti-tumor agents involving the cell-surface and membrane of neoplastic cells. Methodology involves the study of drug effects on specific biologic properties of the cell membrane: transport of amino acids, sugars and nucleosides; maintenance of barriers to uptake of sucrose, mannitol, sulfate, actinomycin D, methotrexate. Biophysical properties of the cell membrane will also be studied: cell charge and cell-surface hydrophobicity, fluorogenic interactions. The ultimate objective of this work is the characterization of cytotoxic interactions between neoplastic cells and specific anti-tumor agents which primarily involve drug effects at membrane sites, rather than drug-induced inhibition of nucleic acid synthesis, or other intracellular events.